The insecticidal neolignan,(+)-haedoxan A, was synthesized from (S)-(+)-β-vinyl-γ- butyrolactone and (2R, 3R)-(+)-6-formyl-7-methoxy-3-methoxymethyl-2-(3, 4- methylenedioxyphenyl)-1, 4-benzodioxane, and its absolute configuration was unequivocally established as 1S, 2R, 5R, 6S, 2 ″R, 3 ″R.